Refactor cluster metric dashboard specs

This refactors cluster metric dashboard specs by extracting some of the
shared examples into their appropriate admin/project/group spec.

ee/spec/controllers/admin/clusters_controller_spec.rb

@@ -48,6 +48,16 @@ describe Admin::ClustersController do
         end
       end
     end
+
+    describe 'GET #metrics_dashboard' do
+      let(:user) { create(:admin) }
+
+      before do
+        sign_in(user)
+      end
+
+      it_behaves_like 'the default dashboard'
+    end
   end
 
   private

ee/spec/controllers/groups/clusters_controller_spec.rb

@@ -78,6 +78,17 @@ describe Groups::ClustersController do
       it { expect { go }.to be_denied_for(:user) }
       it { expect { go }.to be_denied_for(:external) }
     end
+
+    describe 'GET #metrics_dashboard' do
+      let(:user) { create(:user) }
+
+      before do
+        clusterable.add_maintainer(user)
+        sign_in(user)
+      end
+
+      it_behaves_like 'the default dashboard'
+    end
   end
 
   private

ee/spec/controllers/projects/clusters_controller_spec.rb

@@ -70,6 +70,17 @@ describe Projects::ClustersController do
       it { expect { go }.to be_denied_for(:user) }
       it { expect { go }.to be_denied_for(:external) }
     end
+
+    describe 'GET #metrics_dashboard' do
+      let(:user) { create(:user) }
+
+      before do
+        clusterable.add_maintainer(user)
+        sign_in(user)
+      end
+
+      it_behaves_like 'the default dashboard'
+    end
   end
 
   private

ee/spec/support/shared_examples/controllers/cluster_metrics_examples.rb

@@ -186,13 +186,6 @@ shared_examples 'cluster metrics' do
         end
       end
     end
-
-    describe 'GET #metrics_dashboard' do
-      let(:user) { create(:user) }
-  
-      before do
-        clusterable.add_maintainer(user)
-        sign_in(user)
   end
 
   shared_examples_for 'correctly formatted response' do |status_code|
@@ -236,10 +229,6 @@ shared_examples 'cluster metrics' do
     end
   end
 
-      it_behaves_like 'the default dashboard'
-    end
-  end
-
   private
 
   def go